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MXa Series
MX 1000a
MX 1500a
MX 2000a
MX 3000a
®
*TD-000026-00*
A U D I O
Rev. B
1
Owner’s
Manual
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MXa Series Power Amplifier Operation Manual EXPLANATION OF T ABLE OF CONTENTS GRAPHICAL SYMBOLS The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user to the I. WARNING NOTICES................................................. 3 presence of uninsulated “dangerous voltage” within the Speaker Damage ....................................................... 3 product’s enclosure that may be of sufficient magnitude Speaker Output Shock Hazard ..........
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I. WARNING NOTICES CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN SPEAKER DAMAGE CAUTION: To reduce the rish of electric shock, do not remove The MXa Series amplifiers are among the most powerful the cover. No user-serviceable parts inside. Refer servicing to professional amplifiers available and is capable of pro- qualified service personnel. ducing much more power than many loudspeakers can WARNING: To prevent fire or electric shock, do not expose this handle. It is the user’s responsibility to us
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The amplifiers require a rack depth of 18 inches (45.7 cm) II. OVERALL DESCRIPTION to clear the rear support ears. Allow some additional clearance for input and output connectors at the rear panel, which is 16.9 inches (42.9 cm) behind the plane of The MXa Series from QSC comprises four high-effi- the front mounting rails. The built-in cooling fan draws air ciency professional power amplifier models, each with in at the rear of the chassis and exhausts it through vents two independent channels.
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MX 1500a INPUTS III. INPUTS The amplifier’s input sensitivity is 1.07 volt rms; at this An MXa amplifier features balanced inputs, connected signal level and any attenuators set for full gain, the via barrier strip terminals or 1/4” (6.3 mm) tip/ring/sleeve amplifier will produce full rated power—350 watts, 20Hz- phone jacks. The tip of the input jack is wired for “nega- 20kHz, 0.1% THD—into an 8-ohm load. The input imped- tive’ or inverted polarity, while the ring is the non-inverting ance is 2
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IV. OUTPUTS V. OPERATIONS When the amplifier is first turned on, the red “PROT” LED Four “touch-proof” binding posts—one pair per chan- on each channel will light for about three seconds, during nel—on the rear panel allow speaker cable connections which the output relays will stay open to mute the speak- to the amplifier outputs. The special design allows con- ers. After the turn-on muting interval, the “PROT” LEDs nection of large diameter speaker cable while reducing turn off, the green “PWR”
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PROBLEM: Hum in the audio TROUBLESHOOTING • Because of its grounded-collector output transistor configuration, which maximizes PROBLEM: Channel will not come out of muting thermal efficiency, the signal ground on an • If reducing the gain control to ∞ attenuation MXa amplifier cannot be lifted. The amplifier’s does not release muting, the channel is balanced inputs are meant to reject hum, but defective or overheated (see “Overheating,” if hum remains a problem, check the tight- below). ness of
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SPECIFICATIONS FTC Watts Per Channel 20Hz-20kHz, 0.1% THD EIA Watts Per Channel 1kHz, 1% THD MODEL 8Ω Load 4Ω Load 8Ω Load 4Ω Load 2Ω Load* MX 1000a 250 350 275 400 500 MX 1500a 350 500 400 600 750 MX 2000a 450 650 475 725 1000 MX 3000a 800 1200 850 1300 1600 *typical Bridged Mono 20Hz-20kHz, 0.1% THD Bridged Mono 1kHz, 1% THD MODEL 16Ω Load 8Ω Load 4Ω Load* MX 1000a 500 700 1000 MX 1500a 700 1000 1500 MX 2000a 900 1300 2000 MX 3000a 1600 2400 3200 *typical MX 1000a MX 1500a MX 2000a MX 3000a DY
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MX 1000a MX 1500a MX 2000a MX 3000a CONNECTORS (each channel) Input: Barrier strip and 1/4” RTS phone jack Output: “Touch-Proof” binding posts COOLING MX 1000a, MX 1500a, MX 2000a: 2-speed fan with back-to-front air flow MX 3000a: Continuously variable speed fan, with back-to-front air flow ™ AMPLIFIER PROTECTION Output Averaging short-circuit protection, open circuit, ultrasonic, RF, thermal muting (thermal limiting also on MX 3000a). Stable into reactive or mismatched loads. LOAD PROTECTION Tu
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PARALLEL, STEREO, OR BRIDGED INSTRUCTIONS FOR BRIDGED OPERATION OPERATION The Parallel-Stereo-Bridge switch is located on the input 1. Set the switch to the “Bridge” position. panel, next to the input jack for channel 1). 2. Connect the signal to channel 1’s input only. Do not connect anything to the input of The most commonly used operating mode for a power channel 2. amplifier is “Stereo,” in which the two channels are independent and separate all the way from input to 3. Turn up the gain on c
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AC CURRENT CONSUMPTION VI. LONG-TERM OUTPUT A major objective in the design of the MXa Series POWER amplifiers—even the highest-powered models—is to In a properly designed sound system, you can usually permit their operation from readily available, standard obtain the desired sound level without using the full AC power sources. The MX 3000a can deliver 1600 watts output power of the amplifier; if the “CLIP” indicators flash per channel into 2-ohm loads—a total of 3200 watts—yet once in a while,
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HEAT EMISSIONS Essentially, a power amplifier draws electrical energy from the AC mains, converts it to DC, and then converts it again into an analog of the input signal to send out to the loudspeakers. Any AC power that enters the amplifier through the power cord and does not exit through the speaker outputs turns into heat, which the amplifier must rid itself of by exhausting it to the outside. In indoor use this may present a sizeable challenge to a building’s air conditioning system. Use Tab
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output until it can be repaired, at which time the fuse VIII. TECHNICAL ASSISTANCE should be replaced also. & SERVICE Temperature sensors on the channel heatsinks and the power transformers are part of the thermal management circuitry. On the MX 1000a, MX 1500a, and MX 2000a, Servicing your unit requires a trained technician capable the temperature sensors govern whether the dual-speed of performing the type of service you need. There are no fan should run at low or high speed. Below 55˚ C, the
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File Library QUALIFIED SERVICE CENTERS QSControl Hardware Support QSC maintains a service center network for your conve- QSControl Software Support nience. If you choose to return your product to a local EX, MXa, VS, USA, and Series One service center, you may call QSC Technical Services for Slot Accessories General Notes a referral. Accessories, input modules and other periph- eral QSC products must be returned to the factory for File Types service. Graphics Mechanical drawings Specification
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X. IMPORTANT ADDRESS AND TELEPHONE INFORMATION Factory address: QSC Audio Products, Inc. 1675 MacArthur Boulevard Costa Mesa, California 92626-1468 USA Factory telephone numbers: Main Number (714) 754-6175 Sales Direct Line (714) 957-7100 Sales (800) 854-4079 (toll-free in U.S.A. only) Sales & Marketing FAX (714) 754-6174 Customer Service (714) 957-7150 Customer Service (800) 772-2834 (toll-free in U.S.A. only) Customer Service FAX (714) 754-6173 QSC OnLine Technical (714) 668-7567 15
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® A U D I O “QSC” is a registered trademark of QSC Audio Products, Inc. 1675 MacArthur Blvd. Costa Mesa, CA 92626 (714) 754-6175 FAX (714) 754-6174 16
